Guitar Anatomy: Strings, Frets & Intonation Explained

You don’t need to be a luthier to play guitar, but knowing what the parts are called makes every lesson, every tab, and every tuning guide suddenly make sense. Think of this as the reference page you can come back to whenever a term trips you up. We’ll go region by region, then tackle the one piece of setup that quietly ruins more tone than anything else: intonation.

The three regions: headstock, neck, body

Hold a guitar up and you can divide it into three parts.

• The headstock is the top, where the tuning pegs (also called machine heads or tuners) live. Turning them tightens or loosens each string to change its pitch.
• The neck is the long part you fret. Its front face is the fretboard (or fingerboard), and where the neck meets the headstock there’s a small slotted strip called the nut that spaces the strings and sets their height at the top end.
• The body is the big part. On an acoustic it’s a hollow box with a soundhole that projects the sound; on an electric it’s usually solid wood with pickups — magnetic bars under the strings that turn their vibration into a signal for the amp.

The strings and their names

A standard guitar has six strings. From thickest (and lowest-sounding) to thinnest (and highest), the standard tuning is:

E – A – D – G – B – E

The thick low E and the thin high E are two octaves apart — same note name, very different voice. Confusingly, guitarists number the strings the opposite way to how they’re often listed: the thin high E is the 1st string and the thick low E is the 6th string. A classic memory hook for the note names, low to high, is “Eddie Ate Dynamite, Good Bye Eddie.”

Strings are wound metal: the three thin ones are usually plain steel, and the three thick ones are a steel core wrapped in a winding (nickel or bronze, depending on electric vs acoustic). Their thickness — the gauge — changes how they feel and sound, which is a rabbit hole we go down in the restringing guide.

Frets: what they are and how many you get

A fret is one of the thin metal wires running across the fretboard. Pressing a string just behind a fret shortens its vibrating length and raises the pitch. Each fret is one semitone (half step) higher than the last — so moving up one fret on any string is the smallest step in Western music.

How many frets does a guitar have? It depends on the instrument:

• Acoustic guitars typically have 18–20 frets, though only the first 14 or so clear the body comfortably.
• Electric guitars usually have 21, 22, or 24 frets. Twenty-four frets gives you a full two octaves on every string — handy for lead playing and shredding.

The dots (or fancier inlays) you see on the fretboard are just signposts, placed at the 3rd, 5th, 7th, 9th, and 12th frets (and repeating above). The 12th fret is the important one: it’s exactly halfway up the string, so the note there is one octave above the open string. That halfway point matters for the next section.

To actually memorize which note lives at each fret, nothing beats the interactive fretboard — click any dot to hear the note and watch the patterns repeat.

The bridge, saddles, and truss rod

Down on the body, the bridge anchors the strings at the bottom end, and the little ridges the strings rest on are the saddles. On most electrics each string gets its own adjustable saddle — remember that, because it’s the key to intonation. Running inside the neck is the truss rod, an adjustable steel rod that counteracts string tension and keeps the neck from bowing. You rarely touch it, but it’s why a neck stays straight under ~100 pounds of combined string pull.

Intonation: staying in tune up the whole neck

Here’s a problem that surprises new players: a guitar can be perfectly in tune on the open strings and still sound sour when you play chords higher up the neck. That’s an intonation problem — the instrument isn’t in tune with itself along the string.

The cause is geometry. Pressing a string down stretches it slightly sharp, and the fix is to fine-tune the exact length of each string at the saddle. Here’s how to check it:

1. Tune up normally.
2. Play the 12th-fret harmonic (lightly touch the string over the 12th fret) and note the pitch on a tuner.
3. Now play the fretted note at the 12th fret.
4. They should read identically. If the fretted note is sharp, the string is too short — move that saddle back (away from the neck). If it’s flat, move the saddle forward.

On most electrics you can do this yourself with a screwdriver and a tuner. On acoustics the saddle isn’t individually adjustable, so intonation work is a job for a tech. Either way, you need to re-check intonation whenever you change string gauge — heavier or lighter strings sit at a different tension and shift everything. (One more reason the restringing guide and intonation go hand in hand.)

Where this connects

Anatomy isn’t trivia — it’s the map under everything else. Now that the parts have names:

• Those six lines in a tab? They’re these six strings. See how to read guitar tabs.
• Bringing all six strings to pitch is tuning.
• Swapping worn strings (and re-checking intonation afterward) is restringing.

And if you’d like all of it — the fretboard, every chord shape, every scale — in one printable reference you can keep on your music stand, the book below was built for exactly that.